Dorea and her husband Charlus Potter are possibly the grandparents of Harry Potter since they had one son which would be, most likely, James Potter (Harry's father), since unlike in the Muggle world where two people with the same surname can be totally unrelated, wizards with the same names are usually related in some way or another, given the small number of wizarding bloodlines.

Etymology

The name Dorea may come from the names Dora ("gift") or Dorothy, which mean "to see a gift" in Greek (as opposed to "Theodora" which means "a gift from god" in Greek), or from dory, a type of small boat. The name "Dora" appears before Dorea: her great-aunt was named Elladora and her cousin was named Callidora.

Dorea can come from Irish Doireann, which means "sullen" or "daughter of Fionn". Fionn means "fair,white." "Sullen" and "fair,white" can relate to many of the Black family's traits.

Black can be considered a colour, and is the result of the absence of, or complete absorption of, light. In Western culture, the colour black has typically been associated with evil, darkness, and witchcraft, but also with prestige and sophistication — appropriate for the House of Black. Black has also been associated with life and prosperity by other cultures. In ancient China, black was the symbol of the element of water, which also corresponds to Slytherin, the Hogwarts house of almost all members of the Black family. In English heraldry, black represents darkness and ignorance; a possible allusion to the prejudice common to members of the House of Black.

However, the English word black is derived from either the Old English blœc, meaning "black", or blac, meaning "pale".[8]Pallor is associated with sickness and the colour white, which is usually held to symbolize purity in Western and Indian culture, and death in East Asian cultures. This mirrors the typical colouring of members of the House of Black — dark hair and pale skin.

Dorea's married surname is Potter. Potter is a very common surname of English origin.[25] It traditionally refers to the occupation of making pottery. Beatrix Potter was a well-known English children's author. Potter's Field is the name for a burial ground for the unknown or unclaimed dead, particularly soldiers and orphans; It is first mentioned in the Gospel of Matthew, the Potter family had many members that fit that description. The Potter Box is a model for making ethical decisions developed at Harvard University. J. K. Rowling has also commented that she has liked this name since childhood, due to a relationship with two friends who were named Ian and Vikki Potter

Behind the scenes

There is some speculation that Dorea Potter was the mother of James Potter and the paternal grandmother of Harry Potter, given that J. K. Rowling has said that James's parents were older when they had him[3], and Dorea would have been forty years old when he was born[2]. However, Rowling also said that James's parents died of natural causes when they were elderly, presumably around the same time[4]. Dorea died at the age of fifty-seven[2], which is not elderly in wizarding or Muggle terms. This may be a mathematical error, as Rowling has also admitted that maths is not her strong suit[5] and inconsistencies have been noted in the timeline.

Another possibly is that Dorea was an aunt (via marriage) or a distant cousin-in-law to James. If so, then this leaves us with the mystery of what happened to the son of Charlus and Dorea. Since Harry was not supposed to have any living family other than the Dursley family, we could assume that Charlus, Dorea, and their son must have died before 1981.

However, it is also unlikely that Dorea is James Potter's mother as James's parents took Sirius Black into their home after he ran away from his family. As Alphard Black (Sirius' uncle and also Dorea's nephew) was disowned for simply giving Sirius "a decent amount of gold" when he ran away, it's likely that Dorea would also have been disowned for allowing Sirus to live with them.

Also, if Dorea and Charlus were the parents of James, surely he would have been disowned for marrying muggle-bornLily Evans, however from what we have heard of the Potter family, they were not averse to mixing pure and Muggle blood unlike the Blacks, and Dorea, a Slytherin, married Charlus, a Gryffindor, so mixing between members of Hogwarts houses also wasn't an issue for Dorea.

It was also stated that Lily and James had a "quick marriage" and, if it was after Dorea's death, then none of the Black family, apart from Sirius, would have known about it. Then, after this, Lily and James had about a year of marriage, until, around October 31 1979, Harry was conceived and they went into hiding for their own safety, thus keeping them from the world and keeping their marriage a secret.